Brake



Nov. 28, 1933.

W. H. vDELAHAYE BRAKE Filed Dec. 2, 1929 mvENToz! WALTER H. DELAHAYE.

ATTOZN EY- Patented Nov. 28, 1933 UNITED STATES PATENT OFFlC BRAKE Bend, Indiana Application December 2,

8 Claims.

This invention relates to the type of brake in which a-servo action is obtained from a servo shoe, the shoe being mounted to slide on a section of the support for the friction face of one of l the shoes, said section being free of friction material and ofiset inwardly to bring the friction surface of the servo shoe into the same concentric plane as that occupied by the lining covering the remaining section of the shoe. A servo l shoe of this kind is more fully set forth in a number of applicants co-pending applications including appln. No. 410,941, and it is the object of this invention to provide an alternative construction whereby the movement of the servo shoe may be utilized in applying the brakes.

Two modifications of the device are shown b way of example in the accompanying drawing, in which Figure 1 discloses a construction applicable to 0 a pair of cam operated shoes, and

Figure 2 shows an application of the invention to a brake having two points of expansion, one of which is by the customary cam and the other by a toggle coupled to the servo shoe.

Referring to the drawing, in which similar reference characters refer to like parts in both figures, 1 denotes the usual drum and 2 and 3 a pair of shoes anchored on the usual pivot l. The shoes have the usual opposed surfaces 5 and a regulation cam 6 is adapted to operate therebetween. The brake is adapted to be operated in the usual manner by the lever 7 connected to the brake rig g.

The free end of the shoe 2' is adapted to have slidably mounted thereon a servo shoe 8, the shoe 2 having an unlined offset portion 9 to permit such a construction. The servo shoe has inwardly extending portions 10 adapted to be connected to an expanding device which transmits the servo force set up by movement of the servo shoe on its supporting shoe when they are brought into engagement with a rotating drum carried by the part to be braked.

In the construction shown in Figure 1 the part 18 has a pin and slot connection 13 with the end of a lever 11 pivoted .to the free end of the shoe 3 at 12. This lever 11 rests adjacent the pivoted end 12 on a pivot 14 which may be provided with a grooved roller to allow sliding and pivotal movement thereon. The pin and slot connection 13 allows for the initial expansion of the shoes and also for the lateral movement of the servo shoe relative to the lever due to its circumferential movement.

It will be apparent that when the earn 6 ap- 1929. Serial No. 410,940

plies the shoes the servo shoe 8 will partake of the rotary movement of the drum according to direction of drum rotation. When the drum is rotating in a clockwise direction thrust will be imparted by the servo shoe through lever 11 to the .shoe 3, when the drum is rotating in a counterclockwise direction the servo shoe will cause a rocking movement of the lever 11 on the pivot 14 which sets up a powerful applying reaction on the shoe 3.

In the modification shown in Figure 2 the shoes are not anchored as in the modification above described but are connected by a toggle formed by a link 15 and a longer link 16. This latter link extends to a point adjacent the servo shoe 8 and is coupled thereto by a link 17. In all other respects the brake is the same as shown in Figure 1. It will be understood that when the brake is applied the servo shoe will move circumferentially and therefore transmit a force to the link 16 of the toggle, thus applying an additional expaneling effort to the shoes.

It is the intention of the applicant to cover all such forms of the device as may fall within the scope of the appended claims. For the sake oi simplicity the various stops, adjusting means, springs and the like have been omitted as these are well known in the art.

1 claim:

l. In a brake of the class described and in combination with a fixed support therefor, a pair of shoes mounted on the support, one of said shoes comprising a braking section and a servo brake shoe section, means between the ends 0;? the shoes to expand same, a lever pivoted to one end of the shoe not provided with a servo shoe, the other end of said lever being connected to the servo shoe and a fulcrum for the lever adjacent the first mentioned pivot.

22. In a brake of the class described and in combination with a fixed support therefor, a pair oi shoes mounted thereon, a cam between the adjacent iree ends of the shoes, a servo shoe mounted on one of said shoes adjacent its free end, a lever pivoted to one end of the other shoe, a runcrum for the lever adjacent the pivot, the opposite end of the lever being connected to the servo shoe to derive movement therefrom, said movement exerting an additional expanding force on the shoe to which the lever is pivoted.

3. In a brake oi the class described and in com--' bination with a fixed support therefor, a pair of shoes pivoted on the support, means for expanding the free ends of the shoes, a servo shoe carried by one of the shoes adjacent the free end thereof, said servo shoe having a sliding movement in regard thereto, a lever connected to the other shoe adjacent the free end thereof, a fuicrum on the fixed support for the lever, the opposite end of the lever being connected to the servo shoe.

4. In a brake of the class described and in combination with a fixed support therefor, a pair of shoes pivoted on the support,'a cam between ,the free ends for expanding the shoes into en-= gagement with the surface of a drum on the part to be braked, a servo shoe carried on the free end of one of the shoes, being guided thereon to have a sliding movement relative thereto, a lever pivoted to the free end of the other shoe adjacent the free end thereof, a fulcrum on the fixed support on which the lever may have pivotal and sliding movement, the opposite end of the lever being connected to the servo shoe.

5,, In a broke as set forth in claim 4, said lever being connected to the servo shoe by a lost neeaeve motion connection to allow the shoe to travel on its supporting shoe without placing a pull on the lever and on the shoe to which it is pivoted.

6. In a brake as set forth in claim 4, said fulcrum having" a grooved roller on which the lever may ride and said lost motion connection consisting' of a pin and slot connection between the end of the lever and a lug carried by the servo shoe and extending inwardly of the shoes.

7. A brake comprising a pair of shoes, an applying device arranged to separate one pair ofends of said shoes, and a servo shoe carried by one of said shoes and arranged to separate the other ends of said shoes.

8. A brake comprising a pair of shoes, an applying device acting on one pair of ends of said shoes, a lever member acting on the other end of one shoe and connected to the opposite shoe, and a servo member on said opposite shoe acting on said lever member.

WAL'IER H. DELAHAYE. 

